Fantastic fit, like walking on air. Laces are a bonus as no trip hazard

So I bought these trainers couple of months ago and been using for daily walks and two-three more serious hikes. Really comfy from the start and have a good grip. Also breathable and lightweight. However now the sole started making weird and loud crackling sound when walking. Not sure if my trainers are faulty or it’s just the quality but it’s upsetting.. My bf bought the same trainers, we’ll see if it happens to his trainers too